Studies related to understanding the role of polyanionic polysaccharides in the mineralization of skeletal tissues will include isolation, detailed biochemical characterization, and comparisons between hyaluronidase digested peptides from human and bovine proteoglycans and human and avian bone sialoprotein-chondroitin sulfate complexes. Suitable fractions will be used as antigens for studies of cross-reactivity between different classes of polyanions and to study their origin, localization, and changes in distribution in pathologically and experimentally altered tissues and cell cultures.